1. Field of the Invention
This invention relates to medical catheters. It relates especially to a catheter extension set and an assembly for releasably terminating same in an aseptic manner.
2. Background Information
Patients who have kidney failure must be attached periodically to a dialysis machine through which the patient's blood is circulated and cleansed before being returned to the patient. This involves drawing blood from an artery of the patient through an arterial catheter connected to the dialysis machine and returning the cleansed blood to a vein of the patient via a venous catheter. In peritoneal dialysis, blood is drawn from and returned to the patient via the peritoneum. When a patient requires dialysis on a regular basis, the catheters are implanted in the patient with the proximal ends of those catheters being located outside the body and terminated by adapters or connectors, e.g. a Luer connector. Since those catheter connectors and the connectors on the dialysis machine are often made by different manufacturers, they may not be compatible. Therefore, a catheter extension set is often required to match the connector of each implanted catheter to the corresponding connector of the dialysis machine.
A typical extension set includes a length of flexible tubing having different connectors at its proximal and distal ends, the latter of which mates with the connector of the implanted catheter and the former of which is connectable to the dialysis machine. The set may also include a releasable clamp on the tubing for selectively stopping fluid flow therethrough. The catheter extension set usually remains connected to the catheter implanted in the patient.
Typically when a dialysis session is completed, the extension set is decoupled from the dialysis machine and the usual male connector at the proximal end of the set is closed by an end cap which is basically a blind or dead-end version of a female connector. Invariably prior to affixing the end cap, the male connector is sanitized or disinfected by wiping it down with a disinfectant such as alcohol, bleach or betadine. However, I have found through testing that even after such a wipedown, appreciable biological contamination still exists on the connector due to the fact that the connector has exterior threads and crannies which are difficult to reach with a disinfectant wipe. Resultantly, when the connector is again coupled to the mating connector of the dialysis machine, an administration set or other therapeutic apparatus, biological contaminants may be entrained in the fluid flow to the patient giving rise to infection and possible sepsis.
A variety of techniques have been used in an attempt to reduce the frequency of the infections described above. These have included impregnating the catheter connectors with antibiotic or photodynamic substances, incorporating silver or silver compounds in the connectors and irradiating the devices with infrared or ultraviolet light. Each of these prior techniques has, to some extent, reduced the frequency of infection. However, none of them is ideal. An ongoing concern is that microorganisms have the potential to develop resistance to antimicrobials incorporated into the catheter or device in an attempt to prevent infection. Thus, there is an on-going need for an improved mechanism for sanitizing the end fittings of medical catheters generally and catheter extension sets in particular.